1. Field of the Invention
This invention relates to illumination systems that are used in conjunction with ophthalmic surgery for illuminating ocular tissue. More specifically, this invention provides an illumination system that can provide varying color and intensity.
2. Related Art
Currently, illumination systems for illuminating ocular tissue use tungsten, discharge, or fluorescent lamps. These light sources give off a great deal of heat. This heat must be removed by adding cooling fans to the equipment. In addition, because the tungsten and fluorescent lamps convert a significant fraction of the incoming power to heat, a large power supply is required to drive the lamps. The added cooling fans and larger power supply increases the cost of the illumination system.
A tungsten light source has a longevity of approximately 50 hours and produces an extremely bright, hot light.
Ophthalmic surgeons conduct anterior and posterior segment surgery. In general, ophthalmic surgeons will specialize by performing only anterior segment surgery, or by performing only posterior segment surgery. Not surprisingly, due to the variation in tissue and due to the depth of surgery, ophthalmic surgeons have varying preferences on the color of light provided by an illumination system. Ophthalmic surgeons conducting anterior segment surgery have a tendency to prefer an illumination system that will deliver a yellow-red light, while ophthalmic surgeons conducting posterior surgery have a tendency to prefer an illumination system that provides a white-blue light.
In order to accommodate these varying preferences, a rather extensive offering of light filters has been devised to vary the color output of a light source. Thus, one or more light filters must be selected and installed proximate the light source of an illumination system. However, there is variation in the initial color outputs between illumination systems. One tungsten light source may put out an unfiltered light that is slightly different in color from another tungsten light source from the same manufacturer. Thus, what may be the correct filtering choice for a first illumination system may not achieve similar results when the same light filters are installed in a second illumination system. Accordingly, the selection of light filters might not result in the desired color output without some experimentation.